Changes to content/ to facilitate new zoom extension API

content/public/browser/web_contents_observer.h

Index: content/public/browser/web_contents_observer.h
diff --git a/content/public/browser/web_contents_observer.h b/content/public/browser/web_contents_observer.h
index 9fae539faf6e3a97c3198e6d95a3e703202a7982..ef2486d2378b58916d723226170c70675c7e7089 100644
--- a/content/public/browser/web_contents_observer.h
+++ b/content/public/browser/web_contents_observer.h
@@ -11,6 +11,7 @@
 #include "content/public/browser/navigation_controller.h"
 #include "content/public/common/frame_navigate_params.h"
 #include "content/public/common/page_transition_types.h"
+#include "content/public/common/page_zoom.h"
 #include "ipc/ipc_listener.h"
 #include "ipc/ipc_sender.h"
 #include "ui/base/window_open_disposition.h"
@@ -319,6 +320,11 @@ class CONTENT_EXPORT WebContentsObserver : public IPC::Listener,
   virtual void DidAttachInterstitialPage() {}
   virtual void DidDetachInterstitialPage() {}
 
+  // Invoked when a zoom change is initiated from WebContents::SetZoomLevel().
+  virtual void DidSetZoomLevel(int old_zoom_level,
+                               int new_zoom_level,
+                               ZoomMode zoom_mode) {}

[jam, 2014/04/10 21:45:45]

see http://www.chromium.org/developers/content-module/content-api, specifically:

"methods in the API should be there because either content is calling out to its
embedder, or the embedder is calling to content. There shouldn't be any methods
which are used to call from the embedder to the embedder."

since the chrome layer is calling WebContents::SetZoomLevel, we shouldn't have
to tell it back again that it did. whatever code it needs to be done as a result
it should do at the callsites.

+
   // Invoked before a form repost warning is shown.
   virtual void BeforeFormRepostWarningShow() {}